Add .clang-format and apply it

2020/puzzle-01-02.cc

@@ -2,7 +2,8 @@
 #include <string>
 #include <vector>
 
-int main(int argc, char **argv) {
+int main(int argc, char** argv)
+{
   std::vector<int> vals;
   for (std::string line; std::getline(std::cin, line);) {
     int val = std::stoi(line, nullptr, 10);
@@ -12,8 +13,8 @@ int main(int argc, char **argv) {
       for (std::size_t j = 0; j < i; ++j) {
         int64_t v2 = vals[j];
         if (v1 + v2 + val == 2020) {
-          std::cout << v1 << " * " << v2 << " * " << val << " = "
-                    << v1 * v2 * std::int64_t(val) << "\n";
+          std::cout << v1 << " * " << v2 << " * " << val << " = " << v1 * v2 * std::int64_t(val)
+                    << "\n";
         }
       }
     }